|Image credit: NASA / Goddard Space Flight Center Conceptual Image Lab|
The simple story for the public: a dynamo creates the Earth’s magnetic field. The real story: complex scenario needed to start it and keep it running.To face the excerpt and read the rest of the aricle, click on "What You’re Not Being Told About Earth’s Magnetic Field"
Science is often like the two-headed Roman god Janus: one face for the insiders, a different face for the outsiders. Geophysicists have locked themselves into an explanation for the Earth’s magnetic field—the only one, in fact, that offers any hope for keeping it going for billions of years. That theory is the geodynamo theory. Since electromagnetic theory is sufficiently abstruse to keep all but certain college graduates able to fathom its intricacies, only a select few are able to see the problems. But since the public understands what a dynamo is if they know enough to say that a hydroelectric power plant turns a turbine that creates electricity, all the outside-facing face of Janus has to do is smile and say, “a dynamo creates the Earth’s magnetic field.” If asked what runs the dynamo, they have a stock answer: “convection in the Earth’s core.” Since everyone has seen water boil, they can feel satisfied with that explanation.
The public deserves better. When journal articles report problems with commonly-assumed notions like the geodynamo, they should hear about it in language they can understand. Here’s an excerpt from a recent paper in Nature by Anke Wohlers and Bernard Wood, followed by a layman’s translation: